216 Annals Entomological Society of America _[Vol. VII, 
encourage diseases. Another injurious influence was the prac- 
tice of cannibalism among the larvae and also the eating of eggs 
and pupae by both adults and larvae. A female would often 
eat her own eggs. As a rule, these habits were not practiced 
unless there was scarcity of food and in some cases not even 
then, while in other cases these deeds would be perpetrated with 
apparently no excuse. Individuals seemed to differ widely 
in this respect. Some kinds of lice proved injurious in the 
breeding cage. Large lice such as M. rudbeckiae and M. am- 
brosiae Thos., caused the death of several beetles by smearing 
their mouths shut by means of the glue extruded from the corni- 
cles so that the beetles starved to death. Probably the results 
would not have proved fatal, had the beetles not already been 
somewhat weakened by other injurious influences, and were it 
not for the unnatural conditions of the breeding cage so that 
the lice were restless and walking about constantly. 
The larvae, especially in the younger stages, seemed to 
prefer smaller lice in the cages, though out of doors they were 
frequently found feeding on large ones with no apparent diffi- 
culty. This protective function of the cornicles, however, 
would probably, even in nature have more or less of an injurious 
effect on the beetles. 
This ladybeetle seems to be a very general feeder on plant 
lice. One beetle was observed to eat a larva of Aphidoletes 
marina, a dipteron, which is also predaceous on plant lice, but 
whether it would make a practice of this in nature was not 
ascertained, probably not, as in other cases the larvae of A phi- 
doletes were rejected. An unusually hungry beetle or larva 
would often chew or suck about on the leaves which were put 
into the cage with the lice. They seemed to do no visible 
injury to the leaves and were probably only sucking and licking 
off the honey dew left by the aphids. Both the beetles and 
larvae refused to eat chrysomelid eggs and membracid larvae 
which were offered to them. No evidence was obtained of their 
feeding, to any appreciable extent, on anything besides the living 
plant lice. They do not seem to touch even newly laid 
eggs of Aphididae. 
The species of aphididae which were used for food in the 
breeding cage were as follows: Aphis gossypii Glover, A. 
oxybaphi Oest., A. carbocolor Gill., A. torticauda Gill., A. heliantht 
